This invention relates to an improved orthodontic dental bracket, commonly known as braces, to assist in the straightening or repositioning of teeth in the mouth of a patient. More particularly, this invention relates to the addition of notches or apertures in the base plate of the dental bracket which permit dental adhesive to flow into the bracket and form a mechanical lock between the adhesive and the dental bracket.
Orthodontic dental brackets have been in use for many years in the field of dentistry to aid in the correction of misaligned teeth. The dental brackets may be made of metal, porcelain, plastic, or glass and are affixed to the teeth by cleaning the tooth and gluing the bracket to the tooth with a dental adhesive. Dental wire is then threaded from dental bracket to dental bracket and tensioned appropriately. The tensioning of the dental wire provides lateral forces on the tooth via the dental bracket so that over a period of time a patient's teeth are gradually coerced into a desired alignment.
Critical to the successful completion of this process is the requirement that a strong and unbreakable glue bond be formed between the dental bracket and the tooth.
The typical process in bonding a dental bracket to a tooth involves a series of steps substantially as described below.
1. The tooth to which the bracket is to be applied is polished with pumice with a rubber cup polisher to remove debris and to establish clean enamel. PA1 2. The tooth is "conditioned" or etched for 20-60 seconds. The etching is accomplished using an acid-like substance such as phosphoric acid. The etching process removes a smear layer and leaves enamel "tags," or the rods and tubules remaining after etching. The rods and tubules provide some mechanical retention between the glue layer and the tooth. PA1 3. A bonding agent is placed onto the tooth for better retention between the enamel and the glue. The bonding agent is usually an unfilled resin which is either light-cured or self-cured. PA1 4. A dental adhesive is placed on the dental bracket's tooth side surface. This surface usually includes a surface pattern in different directions to provide a "meshwork" pattern. The dental adhesive applied to the tooth is typically either a filled resin, unfilled resin, or various forms of composite resins or glues and is "buttered" onto the meshwork surface of the bracket. For convenience herein, unless the term glue is being used to distinguish one type of dental adhesive from a dental adhesive formed of a different material, the terms dental adhesive and glue will be used synonymously to refer to any dental adhesive. There is a weak mechanical and weak chemical bond between the glue and the bracket meshwork. At this critical point nothing may touch the bracket. Some brackets are pre-glued to speed the process and decrease the chance of contamination. PA1 5. The glued dental bracket is then placed on the tooth and the glue is allowed to cure by itself or cured under a blue light.
In order for the dental bracket to perform its desired function there must be a strong glue-tooth bond and a strong glue-bracket bond. Failure of the glue-tooth bond is rarely experienced; however, the bond between the dental bracket and the glue is found to fail quite often. When the bond fails, the tooth alignment process is interrupted and the bracket must be reattached or a new bracket attached to the tooth. This requires the patient to revisit the orthodontist at an extra unscheduled office visit.
Providing a stronger bond between the dental bracket and the glue will prevent the brackets from separating from the tooth and correspondingly reduce unnecessary visits to the orthodontist. The stronger bond also makes it possible to apply more force to the tooth through the bracket for the orthodontic treatment. Therefore, the purpose of the present invention is to improve the bond between the glue layer and the dental bracket by improving the glue-bracket mechanical bond.